1. Field of the Invention
This invention is generally related to an apparatus and a method for correction based upon detecting a deviation from a proper position of a camera, and more particularly is related to an apparatus for correcting deviation from the proper camera position caused by shaking, such as hand shaking, detected by pairs of acceleration sensors.
2. Background of the Invention
Certain cameras have a function of correcting deviation caused by a slight oscillation based on a hand of an operator holding the camera shaking or by another cause for making the camera shake.
There are some methods for detecting a camera shaking, and such methods utilize devices such as angular velocity sensors, such as a piezoelectric gyro sensor, an acceleration sensor, and an optically detecting sensor. As another method for correcting a camera shaking, an image processing method is also known. The most popular method for addressing camera shaking utilizes a piezoelectric gyro sensor for detecting a rotary motion of the camera body. Furthermore, detecting methods which utilize combinations of the above devices have also been suggested.
When a camera employs a piezoelectric gyro sensor, the piezoelectric gyro sensor detects angular velocity around two axes. After the detection of the angular velocity, an optical system of the camera is adjusted along each axis, a vari-angle control mechanism adjusts a variable rotation angle (Vari-Angle) prism, a reflection mirror in the optical system is adjusted, an image sensing device is moved by a motor, etc. The piezoelectric gyro sensor as an angular velocity sensor which detects the angular velocities along each of the plural axes has been commercialized in a camera.
A method for detecting angular velocity by pairs of acceleration sensors is disclosed in Japanese Laid Open Patent Application 08-101,418 and Japanese Laid Open Patent Application 05-173,219. In the methods disclosed in those documents, the angular acceleration is detected by differential amplifying an output of plural acceleration sensors.
However, the present inventor has realized that the piezoelectric gyro sensor detects the deviation of the camera based upon a resonant of a piezoelectric device, such as a PZT. Therefore, in the system employing the piezoelectric gyro sensor, the system needs a driving circuit which consumes a high power, and a size of the device becomes big as a result of needing that type of driving circuit.
On the other hand, it is easy to accumulate acceleration sensors because an acceleration sensor may utilize a semiconductor production technology by a silicon process. Accordingly, when utilizing accelerator sensors, consumption of electric power is smaller compared with utilizing the piezoelectric gyro sensor, and the size of the device becomes small.
An up-and-down motion of the camera relative to the direction of the optical axis and a side-to-side motion of the camera relative to the direction of the optical axis have the greatest influence on the camera shaking. However, the system disclosed in Japanese Laid Open Patent Application 05-173,219 has only one pair of acceleration sensors and cannot fully detect both these types of movements.
In Japanese Laid Open Patent Application 08-101,418, a system that has plural pairs of acceleration sensors is disclosed. That document, however, does not disclose how to detect and correct for a camera shaking.
Therefore, the above-noted background art systems can not correct for camera shaking based upon rotation based on an up-and-down motion and a side-to-side motion relative to the direction of the optical axis.